ORCID Profile
0000-0002-2067-5270
Current Organisation
University of South Australia
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Publisher: MDPI AG
Date: 02-05-2022
Abstract: Childhood cancer methotrexate (MTX) chemotherapy often causes bone growth impairments, bone loss, and increased risks of fractures during or after treatment, for which the pathobiology is unclear and there is a lack of specific treatment. Our time course analyses of long bones from rats receiving intensive MTX treatment (mimicking a clinical protocol) found decreased trabecular bone volume, increased osteoclast formation and activity, increased adipogenesis in the expense of osteogenesis from the bone marrow stromal cells at days 6 and 9 following the first of five daily MTX doses. For exploring potential mechanisms, PCR array expression of 91 key factors regulating bone homeostasis was screened with the bone s les, which revealed MTX treatment-induced upregulation of Notch receptor NOTCH2, activation of which is known to be critical in skeletal development and bone homeostasis. Consistently, increased Notch2 activation in bones of MTX-treated rats was confirmed, accompanied by increased expression of Notch2 intracellular domain protein and Notch target genes HEY1, HES1 and HEYL. To confirm the roles of Notch2 signalling, a neutralising anti-Notch2 antibody or a control IgG was administered to rats during MTX treatment. Microcomputed tomography analyses demonstrated that trabecular bone volume was preserved by MTX+anti-Notch2 antibody treatment. Anti-Notch2 antibody treatment ameliorated MTX treatment-induced increases in osteoclast density and NFATc1 and RANKL expression, and attenuated MTX-induced bone marrow adiposity via regulating Wnt/β-catenin signalling and PPARγ expression. Thus, Notch2 signalling plays an important role in mediating MTX treatment-induced bone loss and bone marrow adiposity, and targeting Notch2 could be a potential therapeutic option.
Publisher: Wiley
Date: 23-05-2018
DOI: 10.1002/JCP.25936
Abstract: Neurotrophins and their receptors are key molecules that are known to be critical in regulating nervous system development and maintenance and have been recognized to be also involved in regulating tissue formation and healing in skeletal tissues. Studies have shown that neurotrophins and their receptors are widely expressed in skeletal tissues, implicated in chondrogenesis, osteoblastogenesis, and osteoclastogenesis, and are also involved in regulating tissue formation and healing events in skeletal tissue. Increased mRNA expression for neurotrophins NGF, BDNF, NT-3, and NT-4, and their Trk receptors has been observed in injured bone tissues, and NT-3 and its receptor, TrkC, have been identified to have the highest induction at the injury site in a drill-hole injury repair model in both bone and the growth plate. In addition, NT-3 has also recently been shown to be both an osteogenic and angiogenic factor, and this neurotrophin can also enhance expression of the key osteogenic factor, BMP-2, as well as the major angiogenic factor, VEGF, to promote bone formation, vascularization, and healing of the injury site. Further studies, however, are needed to investigate if different neurotrophins have differential roles in skeletal repair, and if NT-3 can be a potential target of intervention for promoting bone fracture healing.
Publisher: MDPI AG
Date: 16-12-2021
DOI: 10.3390/BIOMEDICINES9121926
Abstract: Methotrexate (MTX) treatment for childhood malignancies has shown decreased osteogenesis and increased adipogenesis in bone marrow stromal cells (BMSCs), leading to bone loss and bone marrow adiposity, for which the molecular mechanisms are not fully understood. Currently, microRNAs (miRNAs) are emerging as vital mediators involved in bone/bone marrow fat homeostasis and our previous studies have demonstrated that miR-6315 was upregulated in bones of MTX-treated rats, which might be associated with bone/fat imbalance by directly targeting Smad2. However, the underlying mechanisms by which miR-6315 regulates osteogenic and adipogenic differentiation require more investigations. Herein, we further explored and elucidated the regulatory roles of miR-6315 in osteogenesis and adipogenesis using in vitro cell models. We found that miR-6315 promotes osteogenic differentiation and it alleviates MTX-induced increased adipogenesis. Furthermore, our results suggest that the involvement of miR-6315 in osteogenesis/adipogenesis regulation might be partially through modulating the TGF-β/Smad2 signalling pathway. Our findings indicated that miR-6315 may be important in regulating osteogenesis and adipogenesis and might be a therapeutic target for preventing/attenuating MTX treatment-associated bone loss and marrow adiposity.
Publisher: Wiley
Date: 03-01-2022
DOI: 10.1002/JOR.25253
Abstract: Methotrexate (MTX) is a commonly used antimetabolite in cancer treatment. Its intensive use is linked with skeletal adverse effects such as reduced bone formation and bone loss, and yet little information is available on molecular mechanisms underlying MTX‐induced impaired bone formation. This study investigated the effects of MTX treatment at a clinical chemotherapy relevant dose on osteogenic differentiation in MC3T3E1 osteoblastic cells. To investigate the potential mechanisms, the expression of 87 genes regulating osteoblast differentiation and bone homeostasis was screened in MTX‐treated versus untreated cells by polymerase chain reaction (PCR) arrays and results illustrated significant upregulation of Notch2 and Notch target genes at both early and late stages of MC3T3E1 differentiation following MTX treatment. To confirm the roles of Notch2 pathway and its potential action mechanisms, MC3T3E1 cells were treated with MTX with an anti‐Notch2 neutralizing antibody or control IgG and effects were examined on osteogenesis and activation of the Wnt/ β ‐catenin pathway. Our results demonstrated that induction of Notch2 activity is associated with MTX adverse effects on osteogenic differentiation and blocking Notch2 rescues osteoblast differentiation by preserving activation of the Wnt/ β ‐catenin pathway.
Publisher: Wiley
Date: 25-02-0002
DOI: 10.1002/JBMR.2786
Abstract: Injured growth plate is often repaired by bony tissue causing bone growth defects, for which the mechanisms remain unclear. Because neurotrophins have been implicated in bone fracture repair, here we investigated their potential roles in growth plate bony repair in rats. After a drill-hole injury was made in the tibial growth plate and bone, increased injury site mRNA expression was observed for neurotrophins NGF, BDNF, NT-3, and NT-4 and their Trk receptors. NT-3 and its receptor TrkC showed the highest induction. NT-3 was localized to repairing cells, whereas TrkC was observed in stromal cells, osteoblasts, and blood vessel cells at the injury site. Moreover, systemic NT-3 immunoneutralization reduced bone volume at injury sites and also reduced vascularization at the injured growth plate, whereas recombinant NT-3 treatment promoted bony repair with elevated levels of mRNA for osteogenic markers and bone morphogenetic protein (BMP-2) and increased vascularization and mRNA for vascular endothelial growth factor (VEGF) and endothelial cell marker CD31 at the injured growth plate. When examined in vitro, NT-3 promoted osteogenesis in rat bone marrow stromal cells, induced Erk1/2 and Akt phosphorylation, and enhanced expression of BMPs (particularly BMP-2) and VEGF in the mineralizing cells. It also induced CD31 and VEGF mRNA in rat primary endothelial cell culture. BMP activity appears critical for NT-3 osteogenic effect in vitro because it can be almost completely abrogated by co-addition of the BMP inhibitor noggin. Consistent with its angiogenic effect in vivo, NT-3 promoted angiogenesis in metatarsal bone explants, an effect abolished by co-treatment with anti-VEGF. This study suggests that NT-3 may be an osteogenic and angiogenic factor upstream of BMP-2 and VEGF in bony repair, and further studies are required to investigate whether NT-3 may be a potential target for preventing growth plate faulty bony repair or for promoting bone fracture healing. © 2016 American Society for Bone and Mineral Research.
Publisher: MDPI AG
Date: 02-08-2022
Abstract: Intensive cancer chemotherapy is well known to cause bone vasculature disfunction and damage, but the mechanism is poorly understood and there is a lack of treatment. Using a rat model of methotrexate (MTX) chemotherapy (five once-daily dosses at 0.75 mg/kg), this study investigated the roles of the Notch2 signalling pathway in MTX chemotherapy-induced bone micro-vasculature impairment. Gene expression, histological and micro-computed tomography (micro-CT) analyses revealed that MTX-induced micro-vasculature dilation and regression is associated with the induction of Notch2 activity in endothelial cells and increased production of inflammatory cytokine tumour necrosis factor alpha (TNFα) from osteoblasts (bone forming cells) and bone marrow cells. Blockade of Notch2 by a neutralising antibody ameliorated MTX adverse effects on bone micro-vasculature, both directly by supressing Notch2 signalling in endothelial cells and indirectly via reducing TNFα production. Furthermore, in vitro studies using rat bone marrow-derived endothelial cell revealed that MTX treatment induces Notch2/Hey1 pathway and negatively affects their ability in migration and tube formation, and Notch2 blockade can partially protect endothelial cell functions from MTX damage.
Publisher: MDPI AG
Date: 06-02-2018
DOI: 10.3390/IJMS19020484
Publisher: Wiley
Date: 05-11-2019
DOI: 10.1002/JBMR.3597
Abstract: Dexamethasone (Dex) is known to cause significant bone growth impairment in childhood. Although previous studies have suggested roles of osteocyte apoptosis in the enhanced osteoclastic recruitment and local bone loss, whether it is so in the growing bone following Dex treatment requires to be established. The current study addressed the potential roles of chemokine CXCL12 in chondroclast/osteoclast recruitment and bone defects following Dex treatment. Significant apoptosis was observed in cultured mature ATDC5 chondrocytes and IDG‐SW3 osteocytes after 48 hours of 10 −6 M Dex treatment, and CXCL12 was identified to exhibit the most prominent induction in Dex‐treated cells. Conditioned medium from the treated chondrocytes/osteocytes enhanced migration of RAW264.7 osteoclast precursor cells, which was significantly inhibited by the presence of the anti‐CXCL12 neutralizing antibody. To investigate the roles of the induced CXCL12 in bone defects caused by Dex treatment, young rats were orally gavaged daily with saline or Dex at 1 mg/kg/day for 2 weeks, and received an intraperitoneal injection of anti‐CXCL12 antibody or control IgG (1 mg/kg, three times per week). Aside from oxidative stress induction systemically, Dex treatment caused reductions in growth plate thickness, primary spongiosa height, and metaphysis trabecular bone volume, which are associated with induced chondrocyte/osteocyte apoptosis and enhanced chondroclast/osteoclast recruitment and osteoclastogenic differentiation potential. CXCL12 was induced in apoptotic growth plate chondrocytes and metaphyseal bone osteocytes. Anti‐CXCL12 antibody supplementation considerably attenuated Dex‐induced chondroclast/osteoclast recruitment and loss of growth plate cartilage and trabecular bone. CXCL12 neutralization did not affect bone marrow osteogenic potential, adiposity, and microvasculature. Thus, CXCL12 was identified as a potential molecular linker between Dex‐induced skeletal cell apoptosis and chondroclastic/osteoclastic recruitment, as well as growth plate cartilage/bone loss, revealing a therapeutic potential of CXCL12 functional blockade in preventing bone growth defects during/after Dex treatment. © 2018 American Society for Bone and Mineral Research.
Publisher: Springer Science and Business Media LLC
Date: 17-01-2019
DOI: 10.1007/S00210-019-01613-6
Abstract: Opioids are widely administered to alleviate pain, including chronic pain in advanced cancer patients. Among opioids, morphine is one of the most clinically effective drugs for the palliative management of severe pain. In the last few decades, there has been a debate around the possible influence of opioids such as morphine on tumour growth and metastasis. Whilst several in vitro and in vivo studies suggest the possible modulatory effects of morphine on tumour cells, little is known about the impact of this analgesic drug on other mediators such as matrix metalloproteinases (MMPs) that play a key role in the control of cancer cell invasion and metastasis. MMP-9 has been considered as one of the principal mediators in regulation of not only the initial steps of cancer but during the invasion and spreading of cancer cells to distant organs. Herein, current studies regarding the direct and indirect effects of morphine on regulation of MMP-9 production are discussed. In addition, drawing from previous in vivo and in vitro studies on morphine action in regulating MMP-9 production, the potential roles of several underlying factors are summarised, including nuclear factor kappa-B and intracellular molecules such as nitric oxide.
Publisher: Wiley
Date: 04-12-2019
DOI: 10.1002/JCP.27922
Abstract: Wound healing is a complex but a fine‐tuned biological process in which human skin has the ability to regenerate itself following damage. However, in particular conditions such as deep burn or diabetes the process of wound healing is compromised. Despite investigations on the potency of a wide variety of stem cells for wound healing, adipose‐derived stem cells (ASCs) seem to possess the least limitations for clinical applications, and literature showed that ASCs can improve the process of wound healing very likely by promoting angiogenesis and/or vascularisation, modulating immune response, and inducing epithelialization in the wound. In the present review, advantages and disadvantages of various stem cells which can be used for promoting wound healing are discussed. In addition, potential mechanisms of action by which ASCs may accelerate wound healing are summarised. Finally, clinical studies applying ASCs for wound healing and the associated limitations are reviewed.
Publisher: Springer Science and Business Media LLC
Date: 27-09-2017
DOI: 10.1007/S10456-017-9577-2
Abstract: It is very well known that bone marrow (BM) microvasculature may possess a crucial role in the maintenance of homeostasis of BM due to mutual interactions between BM microvascular system and other physiological functions including haematopoiesis and osteogenesis. Chemotherapy and radiotherapy are known as main approaches for cancer treatment and also are known as the main cause of damage to the BM microvascular system. However, despite the importance of BM microvasculature in orchestrating various biological functions, less attention has been drawn to address the underlying mechanisms for the damage and to explore cellular and molecular mechanisms by which the recovery/regeneration of chemotherapy- and/or radiotherapy-induced BM microvascular system damage can occur. Therefore, in this review we firstly discuss the ultra-/structure and biological characteristics of BM microvascular system (sinusoids). Secondly, potential contribution of BM sinusoids is discussed in pathophysiological circumstances (bone remodelling, haematopoiesis, cancer bone metastasis, and haematological cancers). Thirdly, we address previous preclinical and clinical studies regarding chemotherapy- and irradiation-induced BM microvasculature damage. Finally, potential cellular and molecular mechanisms are discussed for the recovery/regeneration of damaged BM microvascular system, including the potential roles of endothelial progenitor cells, haematopoietic stem rogenitor cells, and stimulation of VEGF/VEGFR and Ang-1/Tie-2 signalling pathways.
Publisher: Elsevier BV
Date: 05-2019
DOI: 10.1016/J.CRITREVONC.2019.01.024
Abstract: Despite more attention to cell migration from circulation into the bone marrow (BM), particularly homing of haematopoietic stem rogenitor cells, the process and mechanisms of cell mobilisation from the BM into the circulation remain largely underexplored. The process of cell mobilisation or transcellular cell migration from BM into the circulation (cell egress) is a crucial biological process in mammals as it is important to maintain homeostasis of various physiological functions including, but not limited to, the immune system, erythropoiesis, platelet release, and stem cell migration. The BM microvascular system composes of a monolayer of specialized endothelial cells, called sinusoidal endothelial cells (SECs). While it is very well evident that the process of cell egress occurs exclusively through BM SECs, there is a lack of systematic analyses addressing the extent of contribution of BM SECs to the process of cell egress from the BM. Therefore, this review aims to address the potential ability of BM SECs in regulating and/or facilitating the process of cell egress from BM. In this review, we address, firstly, the unique ultra-/structural and molecular features of BM SECs and discuss the possible biological interactions between BM SECs and various egressing cells in physiological conditions. Secondly, we propose the potential role of BM SECs in egress of leukemic cells from BM into the circulation. Finally, we discuss the potential role of BM SECs in homing of haematopoietic stem cells. Collectively, the current review suggests that the BM SECs may not be merely a neutral gatekeeper for cell intravasation and extravasation, but rather is a dynamic trafficking surveillance system, thereby the process of BM cell egress/mobilisation can be regulated.
Publisher: Wiley
Date: 22-11-2018
DOI: 10.1002/JCP.27785
Abstract: Cancer chemotherapy can cause significant damage to the bone marrow (BM) microvascular (sinusoidal) system. Investigations must now address whether and how BM sinusoidal endothelial cells (SECs) can be protected during chemotherapy. Herein we examined the potential protective effects of genistein, a soy‐derived flavonoid, against BM sinusoidal damage caused by treatment with methotrexate (MTX). The groups of young adult rats were gavaged daily with genistein (20 mg/kg) or placebo. After 1 week, rats also received daily injections of MTX (0.75 mg/kg) or saline for 5 days and were killed after a further 4 days. Histological analyses showed that BM sinusoids were markedly dilated ( p 0.001) in the MTX‐alone group but were unaffected or less dilated in the genistein+MTX group. In control rats, genistein significantly enhanced expression of vascular endothelial growth factor (VEGF p 0.01), particularly in osteoblasts, and angiogenesis marker CD31 ( p 0.001) in bone. In MTX‐treated rats, genistein suppressed MTX‐induced apoptosis of BM SECs ( p 0.001 vs MTX alone group) and tended to increase expression of CD31 and VEGF ( p 0.05). Our in vitro studies showed that genistein in certain concentrations protected cultured SECs from MTX cytotoxic effects. Genistein enhanced tube formation of cultured SECs, which is associated with its ability to induce expression of endothelial nitric oxide synthase and production of nitric oxide. These data suggest that genistein can protect BM sinusoids during MTX therapy, which is associated, at least partially, with its indirect effect of promoting VEGF expression in osteoblasts and its direct effect of enhancing nitric oxide production in SECs.
Publisher: MDPI AG
Date: 12-10-2021
Abstract: Intensive methotrexate (MTX) treatment for childhood malignancies decreases osteogenesis but increases adipogenesis from the bone marrow stromal cells (BMSCs), resulting in bone loss and bone marrow adiposity. However, the underlying mechanisms are unclear. While microRNAs (miRNAs) have emerged as bone homeostasis regulators and miR-542-3p was recently shown to regulate osteogenesis in a bone loss context, the role of miR-542-3p in regulating osteogenesis and adipogenesis balance is not clear. Herein, in a rat MTX treatment-induced bone loss model, miR-542-3p was found significantly downregulated during the period of bone loss and marrow adiposity. Following target prediction, network construction, and functional annotation/ enrichment analyses, luciferase assays confirmed sFRP-1 and Smurf2 as the direct targets of miR-542-3p. miRNA-542-3p overexpression suppressed sFRP-1 and Smurf2 expression post-transcriptionally. Using in vitro models, miR-542-3p treatment stimulated osteogenesis but attenuated adipogenesis following MTX treatment. Subsequent signalling analyses revealed that miR-542-3p influences Wnt/β-catenin and TGF-β signalling pathways in osteoblastic cells. Our findings suggest that MTX treatment-induced bone loss and marrow adiposity could be molecularly linked to miR-542-3p pathways. Our results also indicate that miR-542-3p might be a therapeutic target for preserving bone and attenuating marrow fat formation during/after MTX chemotherapy.
Publisher: Public Library of Science (PLoS)
Date: 12-08-2013
Publisher: Wiley
Date: 27-09-2019
DOI: 10.1002/JCB.27705
Abstract: Cancer treatments with cytotoxic drugs have been shown to cause bone loss. However, effects on bone are less clear for ErbB‐targeting tyrosine kinase inhibitors or their combination use with cytotoxic drugs. This study examined the effects of in idual or combination treatments with breast cancer drugs lapatinib (a dual ErbB1/ErbB2 inhibitor) and paclitaxel (a microtubule‐stabilizing cytotoxic agent) on bone and bone marrow of rats. Wistar rats received lapatinib (240 mg/kg) daily, paclitaxel (12 mg/kg) weekly, or their combination for 4 weeks, and effects on bone/bone marrow were examined at the end of week 4. Microcomputed tomographical structural analyses showed a reduction in trabecular bone volume in tibia following the lapatinib, paclitaxel or their combination treatments ( P 0.05). Histomorphometry analyses revealed marked increases in bone marrow adipocyte contents in all treatment groups. Reverse transcription polymerase chain reaction gene expression studies with bone s les and cell culture studies with isolated bone marrow stromal cells showed that the all treatment groups displayed significantly reduced levels of osterix expression and osteogenic differentiation potential but increased expression levels of adipogenesis transcription factor peroxisome proliferator‐activated receptor γ. In addition, these treatments suppressed the expression of Wnt10b and/or increased expression of Wnt antagonists (secreted frizzled‐related protein 1, Dickkopf‐related protein 1 and/or sclerostin). Furthermore, all treatment groups showed increased numbers of bone‐resorbing osteoclasts on trabecular bone surfaces, although only the lapatinib group displayed increased levels of osteoclastogenic signal (receptor activator of nuclear factor κΒ ligand/osteoclastogenesis inhibitor osteoprotegrin expression ratio) in the bones. Thus, inhibiting ErbB1 and ErbB2 by lapatinib or blocking cell ision by paclitaxel or their combination causes significant trabecular bone loss and bone marrow adiposity involving a switch in osteogenesis/adipogenesis potential, altered expression of some major molecules of the Wnt/β‐catenin signalling pathway, and increased recruitment of bone‐resorbing osteoclasts.
Publisher: MDPI AG
Date: 09-03-2017
DOI: 10.3390/NU9030255
Publisher: American Physiological Society
Date: 06-2012
DOI: 10.1152/AJPENDO.00587.2011
Abstract: Cancer chemotherapy can cause osteopenia or osteoporosis, and yet the underlying mechanisms remain unclear, and currently, no preventative treatments are available. This study investigated damaging effects of 5-fluorouracil (5-FU) on histological, cellular, and molecular changes in the tibial metaphysis and potential protective benefits of emu oil (EO), which is known to possess a potent anti-inflammatory property. Female dark agouti rats were gavaged orally with EO or water (1 ml·day −1 ·rat −1 ) for 1 wk before a single ip injection of 5-FU (150 mg/kg) or saline (Sal) was given. The treatment groups were H 2 O + Sal, H 2 O + 5-FU, EO + 5-FU, and EO + Sal. Oral gavage was given throughout the whole period up to 1 day before euthanasia ( days 3, 4, and 5 post-5-FU). Histological analysis showed that H 2 O + 5-FU significantly reduced heights of primary spongiosa on days 3 and 5 and trabecular bone volume of secondary spongiosa on days 3 and 4. It reduced density of osteoblasts slightly and caused an increase in the density of osteoclasts on trabecular bone surface on day 4. EO supplementation prevented reduction of osteoblasts and induction of osteoclasts and bone loss caused by 5-FU. Gene expression studies confirmed an inhibitory effect of EO on osteoclasts since it suppressed 5-FU-induced expression of proinflammatory and osteoclastogenic cytokine TNFα, osteoclast marker receptor activator of nuclear factor-κB, and osteoclast-associated receptor. Therefore, this study demonstrated that EO can counter 5-FU chemotherapy-induced inflammation in bone, preserve osteoblasts, suppress osteoclast formation, and potentially be useful in preventing 5-FU chemotherapy-induced bone loss.
Publisher: Elsevier BV
Date: 11-2018
Publisher: American Chemical Society (ACS)
Date: 28-12-2022
Publisher: Wiley
Date: 17-12-2013
DOI: 10.1002/JOR.22565
Abstract: Methotrexate (MTX) chemotherapy is known to cause bone loss which lacks specific preventative treatments, although clinically folinic acid is often used to reduce MTX toxicity in soft tissues. This study investigated damaging effects of MTX injections (0.75 mg/kg/day for 5 days) in rats and potential protective benefits of fish oil (0.25, 0.5, or 0.75 ml/100 g/day) in comparison to folinic acid (0.75 mg/kg) in the tibial metaphysis. MTX treatment significantly reduced height of primary spongiosa and volume of trabecular bone while reducing density of osteoblasts. Consistently, MTX reduced osteogenic differentiation but increased adipogenesis of bone marrow stromal cells, accompanied by lower mRNA expression of osteogenic transcription factors Runx2 and Osx, but an up-regulation of adipogenesis-related genes FABP4 and PPAR-γ. MTX also increased osteoclast density, bone marrow osteoclast formation, and mRNA expression of proinflammatory cytokines IL-1, IL-6, TNF-α, and RANKL/OPG ratio in bone. Fish oil (0.5 or 0.75 ml/100 g) or folinic acid supplementation preserved bone volume, osteoblast density, and osteogenic differentiation, and suppressed MTX-induced cytokine expression, osteoclastogenesis, and adipogenesis. Thus, fish oil at 0.5 ml/100 g or above is as effective as folinic acid in counteracting MTX-induced bone damage, conserving bone formation, suppressing resorption and marrow adiposity, suggesting its therapeutic potential in preventing bone loss during MTX chemotherapy.
Publisher: Wiley
Date: 12-09-2022
DOI: 10.1002/JCP.30583
Abstract: Previous studies have shown that administration of antimetabolite methotrexate (MTX) caused a reduced trabecular bone volume and increased marrow adiposity (bone/fat switch), for which the underlying molecular mechanisms and recovery potential are unclear. Altered expression of microRNAs (miRNAs) has been shown to be associated with dysregulation of osteogenic and/or adipogenic differentiation by disrupting target gene expression. First, the current study confirmed the bone/fat switch following MTX treatment in precursor cell culture models in vitro. Then, using a rat intensive 5‐once daily MTX treatment model, this study aimed to identify miRNAs associated with bone damage and recovery (in a time course over Days 3, 6, 9, and 14 after the first MTX treatment). RNA isolated from bone s les of treated and control rats were subjected to miRNA array and reverse transcription‐polymerase chain reaction validation, which identified five upregulated miRNA candidates, namely, miR‐155‐5p, miR‐154‐5p, miR‐344g, miR‐6215, and miR‐6315. Target genes of these miRNAs were predicted using TargetScan and miRDB. Then, the protein‐protein network was established via STRING database, after which the miRNA‐key messenger RNA (mRNA) network was constructed by Cytoscape. Functional annotation and pathway enrichment analyses for miR‐6315 were performed by DAVID database. We found that TGF‐β signaling was the most significantly enriched pathway and subsequent dual‐luciferase assays suggested that Smad2 was the direct target of miR‐6315. Our current study showed that miR‐6315 might be a vital regulator involved in bone and marrow fat formation. Also, this study constructed a comprehensive miRNA–mRNA regulatory network, which may contribute to the pathogenesis rognosis of MTX‐associated bone loss and bone marrow adiposity.
Publisher: MDPI AG
Date: 11-06-2023
Publisher: Wiley
Date: 12-01-2021
DOI: 10.1002/JCP.30278
Abstract: Intensive use of methotrexate (MTX) and/or dexamethasone (DEX) for treating childhood malignancies is known to cause chondrocyte apoptosis and growth plate dysfunction leading to bone growth impairments. However, mechanisms remain vague and it is unclear whether MTX and DEX combination treatment could have additive effects in the growth plate defects. In this study, significant cell apoptosis was induced in mature ATDC5 chondrocytes after treatment for 48 h with 10 −5 M MTX and/or 10 −6 M DEX treatment. PCR array assays with treated cells plus messenger RNA and protein expression confirmation analyses identified chemokine CXCL12 having the most prominent induction in each treatment group. Conditioned medium from treated chondrocytes stimulated migration of RAW264.7 osteoclast precursor cells and formation of osteoclasts, and these stimulating effects were inhibited by the neutralizing antibody for CXCL12. Additionally, while MTX and DEX combination treatment showed some additive effects on apoptosis induction, it did not have additive or counteractive effects on CXCL12 expression and its functions in enhancing osteoclastic recruitment and formation. In young rats treated acutely with MTX, there was increased expression of CXCL12 in the tibial growth plate, and more resorbing chondroclasts were found present at the border between the hypertrophic growth plate and metaphysis bone. Thus, the present study showed an association between induced chondrocyte apoptosis and stimulated osteoclastic migration and formation following MTX and/or DEX treatment, which could be potentially or at least partially linked molecularly by CXCL12 induction. This finding may contribute to an enhanced mechanistic understanding of bone growth impairments following MTX and/or DEX therapy.
Publisher: Wiley
Date: 20-10-2021
DOI: 10.1002/JCP.30114
Abstract: Cancer chemotherapy can significantly impair the bone formation and cause myelosuppression however, their recovery potentials and mechanisms remain unclear. This study investigated the roles of the β‐catenin signaling pathway in bone and bone marrow recovery potentials in rats treated with antimetabolite methotrexate (MTX) (five once‐daily injections, 0.75 mg/kg) with/without β‐catenin inhibitor indocyanine green (ICG)‐001 (oral, 200 mg/kg/day). ICG alone reduced trabecular bone volume and bone marrow cellularity. In MTX‐treated rats, ICG suppressed bone volume recovery on Day 11 after the first MTX injection. ICG exacerbated MTX‐induced decreases on Day 9 osteoblast numbers on bone surfaces, their formation in vitro from bone marrow stromal cells (osteogenic differentiation/mineralization), as well as expression of osteogenesis‐related markers Runx2, Osx, and OCN in bone, and it suppressed their subsequent recoveries on Day 11. On the other hand, ICG did not affect MTX‐induced increased osteoclast density and the level of the osteoclastogenic signal (RANKL/OPG expression ratio) in bone, suggesting that ICG inhibition of β‐catenin does nothing to abate the increased bone resorption induced by MTX. ICG also attenuated bone marrow cellularity recovery on Day 11, which was associated with the suppressed recovery of CD34 + or c‐Kit + hematopoietic progenitor cell contents. Thus, β‐catenin signaling is important for osteogenesis and hematopoiesis recoveries following MTX chemotherapy.
Publisher: Wiley
Date: 13-01-2019
DOI: 10.1002/JCP.28141
Abstract: Critical limb ischemia (CLI) is the advanced stage of peripheral artery disease spectrum and is defined by limb pain or impending limb loss because of compromised blood flow to the affected extremity. Current conventional therapies for CLI include utation, bypass surgery, endovascular therapy, and pharmacological approaches. Although these conventional therapeutic strategies still remain as the mainstay of treatments for CLI, novel and promising therapeutic approaches such as proangiogenic gene rotein therapies and stem cell‐based therapies have emerged to overcome, at least partially, the limitations and disadvantages of current conventional therapeutic approaches. Such novel CLI treatment options may become even more effective when other complementary approaches such as utilizing proper bioscaffolds are used to increase the survival and engraftment of delivered genes and stem cells. Therefore, herein, we address the benefits and disadvantages of current therapeutic strategies for CLI treatment and summarize the novel and promising therapeutic approaches for CLI treatment. Our analyses also suggest that these novel CLI therapeutic strategies show considerable advantages to be used when current conventional methods have failed for CLI treatment.
Publisher: Elsevier BV
Date: 03-2013
DOI: 10.1016/J.JAUT.2013.01.001
Abstract: Psoriasis, a chronic inflammatory skin disorder, is characterized by aberrant keratinocyte proliferation and differentiation in the epidermis. Although the pathogenesis of psoriasis is still incompletely understood, both genetic susceptibilities and environmental triggers are known to act as key players in its development. Several studies have suggested that DNA methylation is involved in the pathogenesis of psoriasis. However, the precise mechanisms underlying the regulation and maintenance of the methylome as well as their relationship with this disease remain poorly characterized. Herein, we used methylated DNA immunoprecipitation sequencing (MeDIP-Seq) to characterize whole-genome DNA methylation patterns in involved and uninvolved skin lesions from patients with psoriasis. The results of our MeDIP-Seq analyses identified differentially methylated regions (DMRs) covering almost the entire genome with sufficient depth and high resolution, showing that the number of hypermethylated DMRs was considerably higher than that of hypomethylated DMRs in involved psoriatic skin s les. Moreover, gene ontology analysis of MeDIP-Seq data showed that the aberrantly methylated genes belonged to several different ontological domains, such as the immune system, cell cycle and apoptosis. The results of the bisulfite-sequencing experiments for the genes PDCD5 and TIMP2 confirmed the methylation status identified by MeDIP-Seq, and the mRNA expression levels of these two genes were consistent with their DNA methylation profiles. To our knowledge, the present study constitutes the first report on MeDIP-Seq in psoriasis. The identification of whole-genome DNA methylation patterns associated with psoriasis provides new insight into the pathogenesis of this complex disease and represents a promising avenue through which to investigate novel therapeutic approaches.
Publisher: Wiley
Date: 14-09-2019
DOI: 10.1002/JCB.27589
Abstract: Chemotherapeutic agents are very well evident extrinsic stimuli for causing damage to endothelial cells. Methotrexate is an antimetabolite commonly used to treat solid tumours and paediatric cancers. However, studies on the effect(s) of methotrexate on bone marrow microvascular system are inadequate. In the current study, we observed a significant bone marrow microvascular dilation following methotrexate therapy in rats, accompanied by apoptosis induction in bone marrow sinusoidal endothelial cells, and followed by recovery of bone marrow sinusoids associated with increased proliferation of remaining bone marrow sinusoidal endothelial cells. Our in vitro studies revealed that methotrexate is cytotoxic for cultured sinusoidal endothelial cells and can also induce apoptosis which is associated with upregulation of expression ratio of Bax and Bcl‐2 genes and Bax/Bcl‐2 expression ratio. Furthermore, it was shown that methotrexate can negatively affect proliferation of cultured sinusoidal endothelial cells and also inhibit their abilities of migration and formation of microvessel like tubes. The data from this study indicates that methotrexate can cause significant bone marrow sinusoidal endothelium damage in vivo and induce apoptosis and inhibit proliferation, migration and tube‐forming abilities of sinusoidal endothelial cells in vitro.
Publisher: Wiley
Date: 29-06-2017
DOI: 10.1111/NYAS.13380
Abstract: Intensive cancer chemotherapy causes significant bone loss, for which the mechanisms remain unclear and effective treatments are lacking. This is a significant issue particularly for childhood cancers, as the most common ones have a >75% cure rate following chemotherapy there is an increasing population of survivors who live with chronic bone defects. Studies suggest that these defects are the result of reduced bone from increased marrow fat formation and increased bone resorption following chemotherapy. These changes probably result from altered expression/activation of regulatory molecules or pathways regulating skeletal cell formation and activity. Treatment with methotrexate, an antimetabolite commonly used in childhood oncology, has been shown to increase levels of proinflammatory ro-osteoclastogenic cytokines (e.g., enhanced NF-κB activation), leading to increased osteoclast formation and bone resorption, as well as to attenuate Wnt signaling, leading to both decreased bone and increased marrow fat formation. In recent years, understanding the mechanisms of action and potential health benefits of selected nutraceuticals, including resveratrol, genistein, icariin, and inflammatory fatty acids, has led to preclinical studies that, in some cases, indicate efficacy in reducing chemotherapy-induced bone defects. We summarize the supporting evidence.
No related grants have been discovered for Yu-Wen SU.